The present research investigates the role of project management office in project efficiency and thus its success. The statistical population used in this work includes construction corporations active in the Iran construction industry and familiar with the concept of project management office. In such organizations, existence of the project management office and the success of their projects is firstly assessed and the role of the project management office in success of the organization’s project as well as comparison of them with each other is then studied. For this purpose, a quantitative research methodology in the form of survey, along with designing a questionnaire with the help of 5-point Likert scale have been used. The results obtained indicate the existence of a highly strong linear relationship between the existence of project management office and the success of project. The results also show that the more highlighted the features of this office such as methods and standards for project management, project history archive, cooperation between employees/human resources office, project management educating and project administrative support, the more the success aspect of the project will be. Finally, the mentioned inferential statistics and qualitative features lead to generation of practical guidelines for organizations which have or are seeking to establish project management office. DOI: 10.5901/mjss.2015.v6n6s2p325